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Titolo:
THE BIOGEOCHEMISTRY OF PRISTINE, HEADWATER PRECAMBRIAN SHIELD WATERSHEDS - AN ANALYSIS OF MATERIAL TRANSPORT WITHIN A HETEROGENEOUS LANDSCAPE
Autore:
ALLAN CJ; ROULET NT; HILL AR;
Indirizzi:
UNIV N CAROLINA,DEPT GEOG & EARTH SCI CHARLOTTE NC 28223 YORK UNIV,DEPT GEOG N YORK M3J 1P3 ONTARIO CANADA
Titolo Testata:
Biogeochemistry
fascicolo: 1, volume: 22, anno: 1993,
pagine: 37 - 79
SICI:
0168-2563(1993)22:1<37:TBOPHP>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
EXPERIMENTAL LAKES AREA; NORTHWESTERN ONTARIO; NATURAL-WATERS; CHEMISTRY; UNCERTAINTIES; PHOSPHORUS; BUDGETS; FOREST; NORWAY;
Keywords:
ELEMENTAL TRANSPORT; HYDROLOGIC PATHWAYS; SPATIAL HETEROGENEITY; PRECAMBRIAN SHIELD;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
36
Recensione:
Indirizzi per estratti:
Citazione:
C.J. Allan et al., "THE BIOGEOCHEMISTRY OF PRISTINE, HEADWATER PRECAMBRIAN SHIELD WATERSHEDS - AN ANALYSIS OF MATERIAL TRANSPORT WITHIN A HETEROGENEOUS LANDSCAPE", Biogeochemistry, 22(1), 1993, pp. 37-79

Abstract

The hydrology and elemental transport within five low order Precambrian shield catchments was investigated during 1988-90. Catchments were subdivided and instrumented to examine the vertical and horizontal fluxes of elements within and between two distinct landscape types: open,lichen-covered bedrock outcrops and patches of conifer forest. The dominant hydrologic pathways were Horton overland flow in the lichen-bedrock areas and shallow subsurface flow through organic rich LFH (forest floor) and Ah soil horizons in the forested areas. Annual runoff coefficients ranged from 0.3 to 0.7. Runoff chemistry was acidic (pH 4.01-4.72), with organic anion equivalents (RCOO-), comprising 60 and 69% of the anion charge total for bedrock and forest runoff, respectively. Forested plots exported more H+ (2.6x), DOC (1.4x), Al (1.6x) and Fe (1.8x) and less N (0.40x), P (0.13x), particulate C (0.08x), Ca2+ (0.38x), Mg2+ (0.83x), Na+ (0.85x) and K+ (0.32x) per unit area than the bedrock-lichen plots. The catchments exhibited a net export of H+ (34),Mg2+ (24), Na+ (20), K+ (4) (units in eq ha-1 yr-1) and C (16), Si (5.6), Al (1.6) and Fe (0.47) (units kg ha-1 yr-1). The catchments retained N (5.66), P (0.08), Mn (0.03) (units kg ha-1 yr-1), and Ca2+ (37),and Cl- (3) (units eq ha-1 yr-1). The strong retention of Ca2+ withinthe treed soil islands resulted in extremely low export rates of basecations (-15 to 38 eq ha-1 yr-1). The spatial distribution and hydrologic and biogeochemical linkages associated with each landscape unit interact to control element transport within the study catchments.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 05:07:38